AMD64/IA64/x86 This doesn’t tell you the architecture of the processor but only of the current process, so it returns “x86” for a 32 bit WOW process running on 64 bit Windows. See detecting OS 32/64 bit

%PROCESSOR_ARCHITEW6432%

=%ProgramFiles% (only available on 64 bit systems)

%PROCESSOR_IDENTIFIER%

Processor ID of the user’s workstation.

%PROCESSOR_LEVEL%

Processor level of the user’s workstation.

%ProgramW6432%

=%PROCESSOR_ARCHITECTURE% (only available on 64 bit systems)

%ProgramData%

C:\ProgramData

%ProgramFiles%

C:\Program Files

%ProgramFiles(x86)%

C:\Program Files (x86)

%PSModulePath%

%SystemRoot%\system32\WindowsPowerShell\v1.0\Modules\

%Public%

C:\Users\Public

%RANDOM%

A random decimal number between 0 and 32767.

%SYSTEMDRIVE%

C:

%SYSTEMROOT%

C:\Windows

%TEMP% and %TMP%

C:\Users\{Username}\AppData\Local\Temp
Under XP this was \{username}\Local Settings\Temp

%TIME%

The current time using same format as TIME.

%USERNAME%

{username}

%USERPROFILE%

%SystemDrive%\Users\{username}
This is equivalent to the $HOME environment variable in Unix/Linux